Prince William's major priority before becoming King - despite being hit by criticism

From tackling climate change and saving the oceans to trying to solve the homelessness crisis, Prince William seems to be a man on a mission.

In recent months the Prince of Wales has been carrying out work linked to a range of causes close to his heart - including mental health and the climate crisis - combining it with the pomp and pageantry of royal events such as Trooping the Colourand the ancient Order of the Garter ceremony.

But today, he will surely be swapping any work matters for precious family time with the Princess of Wales and their children as he celebrates his 43rd birthday. A year ago, William was in a very different place, as wife Kate was still undergoing chemotherapy treatment after her cancer diagnosis. At the same time, his father the King has also been diagnosed with the disease.

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Not only was he on hand to support them both, but he also proved to be a rock for his three children Prince George, Princess Charlotte and Prince Louis.

He memorably described 2024 as "brutal" and significantly one of the "hardest of his life". But with Kate now in remission, things look different 12 months on as he turns a year older, focus shifts slightly to duty.

In the past week, not only has he been at Trooing and Garter Day but also Royal Ascot and carried out a visit alongside actress Cate Blanchett to Colorifix - a Norwich-based company which creates sustainable dye for clothing, and is one of his Earthshot Prize finalists.

And former BBC royal correspondent Jennie Bond tells the Mirror that William is "extremely serious" when it comes to the job that his life has given him.

She explained: "As he himself has said, if he can't make some kind of difference, some kind of impact on issues he cares so deeply about – then what is the point of being a prince or of having such a high profile platform?

"So, now that the crisis of the past 18 months has eased, he seems to be working pretty much flat out for much of the time, and I'm sure that will continue." But despite his work and duty, there is one thing that always comes first for William as well as wife Kate - family.

William is a very hands-on parent, doing the school run and ferrying the kids to their various after-school sports clubs and activities. Putting family first was no more so evident than at Easter earlier this year when he and his family skipped the traditional Easter Sunday church service with the King and Queen at Windsor to spend precious family time together - all with the King's blessing.

And even if his schedule may seem busier, Jennie believes this family time is something William will always make a priority. She said: "These years are a period when, without the never-ending state duties of a monarch, he can be allowed to concentrate rather more fully on his wife and children. So I think school holidays will continue to be ring-fenced as much as possible, even if he is criticised for doing so.

"You just have to look at the pictures of William and his children released for Father's Day to see how much they adore him and how close they are as a family. This tall, handsome, smiling man is their dad and their protector. And William would never want to put that in any jeopardy."

It's not known exactly what type of birthday celebration will be in store for William today - but no doubt it will involve Kate and the kids.

Last year, Kate shared an incredible photo of her husband and three children leaping over sand dunes in Norfolk with the message: "Happy birthday Papa, we all love you so much! Cx" His father the King also shared a baby photo of the Prince sitting on his lap.

And Jennie added: "His birthday is on a Saturday this year, so there’ll be a chance for a family celebration. I doubt it will be anything particularly grand - it’s more likely they’ll enjoy a family barbecue and a romp around the garden or beach."